Marco and Alex started as rivals, both running for Degrassi's student presidency. Marco ended up being elected student president, and appointed Alex as vice president. As the two worked together, Alex's attitude softened and the two eventually became close friends.
In King of Pain, when Marco decides to run for Student Council President, his opponent Alex decides to play dirty politics by threatening to reveal his homosexuality at the Election assembly, which his dad is going to attend. Many of Marco's friends, including Paige Michalchuk, Craig Manning, Spinner Mason, and Hazel Aden, were shocked when they learned that Alex is going to run.Once the day of the big debate comes, Alex reveals her campaign as her being a "freak", but even though she threatened Marco about his sexuality, she decides to keep it a secret, deciding at the last minute that it is wrong to use homophobia as a winning tactic. However, Marco ends up winning the presidential position and, in a move of forgiveness, happily makes Alex his vice president. This marks the beginning of their friendship.
In The Lexicon of Love (2), Paige tells Marco that she is the object of a girl's affections, but when Alex chooses to sit away from the two, Marco figures out that Alex likes Paige. Paige reveals to him that Alex kissed her last night. Alex begins to date Marco's close friend, Paige. Marco is happy for them both. In I Against I, he refers to the couple as Palex.
In High Fidelity (1), they are in the same class together with Hazel and Paige.
In High Fidelity (2), Marco and Alex graduate with their classmates.
In Free Fallin' (2), Marco, Alex, Spinner, Paige, and Jimmy all go out to karaoke. Marco sings to Alex while singing karaoke.
- They are both part of the LGBT community.
- They both dated the opposite sex before coming out: Marco dated Ellie Nash while Alex dated Jay Hogart.
- They both graduated in the Class of 2006.
- They are both openly gay.
- They were both close to Paige: Alex dated her and Marco was her close friend.
- They are both friends with Ellie Nash and Jimmy Brooks.
- Marco Del Rossi and Alex Nuñez were President and Vice President respectively of the Degrassi Student Council from 2004 to 2005.
- In King of Pain, Marco's best friend Craig Manning described Alex as "most likely to succeed in killing someone."
- Alex's ex-boyfriend Jay disliked Marco because he was gay.
- They were both members of the Degrassi Drama Department.
- They briefly lived together in 2007.